I have a problem with a host, I can no longer get the agent output; I tried to check selinux, the firewall, I updated the agent, I removed xinetd and tried with the check_mk.socket service; when I tried telnet (also from localhost) on port 6556 connects but does not exit the output of the agent.
Does anyone have any suggestions?
I’m using the latest version of checkmk raw edition.
Thanks in advance
What is the output when you run the agent from the command line of the host? As root run:
/usr/bin/check_mk_agent
I see the correct output (all the sections of the agent), but if i try a telnet on localhost 6556 the output is empty, i see “connected on port 6556” but i don’t see the output of the agent like others host.
Which program is listening on Port 6556/tcp? Check with ss -tlnp | fgrep:6556 as root.
If it is xinetd, then you might have some access restrictions in the xinetd service definition (probably /etc/xinetd.d/check_mk) or in /etc/hosts.allow and /etc/hosts.deny
Perhaps you can also find some hint in the logs.
Which OS (distribution+version) is this, btw?
ss -tlnp | grep 6556
LISTEN 0 64 :::6556 :::* users:((“xinetd”,pid=24059,fd=5))
I have no access restrictions on the files you mentioned.
The operating system is centos 7.5.1804
This is a cluster and the other nodes have the same configuration and are able to monitor them.
This node was also properly monitored, but after a reboot I encountered this problem.
So xinetd, ok.
I’m not really familiar with CentOS, so perhaps there are some other pitfalls I might not be aware of
How does the xinetd service definition look like?
You could enable xinetd debug mode (-d option, see man page).
This is the output of xinetd -d:
Service defaults
Instances = 50
Groups = yes
umask = 2
CPS = max conn:50 wait:10
PER_SOURCE = 10
Bind = All addresses.
Only from: All sites
No access: No blocked sites
Logging to syslog. Facility = daemon, level = info
Log_on_success flags = HOST DURATION EXIT PID
Log_on_failure flags = HOST
Service configuration: check_mk
id = check_mk
flags = IPv6
type = UNLISTED
socket_type = stream
Protocol (name,number) = (tcp,6)
port = 6556
wait = no
user = 0
Groups = yes
umask = 2
PER_SOURCE = 3
Bind = All addresses.
Server = /usr/bin/check_mk_agent
Server argv = check_mk_agent
Only from: All sites
No access: No blocked sites
Logging to syslog. Facility = daemon, level = info
Log_on_success flags =
Log_on_failure flags = HOST
22/3/14@15:56:02: ERROR: 25270 {activate_normal} bind failed (Address already in use (errno = 98)). service = check_mk
22/3/14@15:56:02: ERROR: 25270 {cnf_start_services} Service check_mk failed to start and is deactivated.
22/3/14@15:56:02: DEBUG: 25270 {cnf_start_services} pfds_last = 1, services_started = 0
22/3/14@15:56:02: CRITICAL: 25270 {init_services} no services. Exiting…
You probably need stop the normal xinetd first before starting a debug instance.
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